The presence of radioactive materials in water can come about due to the actions of mankind as well as acts of nature. For instance, while contamination of ground and surface waters can come about as a result of the release of radioactive material from various types of industrial and research facilities, in other cases, the presence of radioactive materials in ground or surface waters is due merely to the presence of these materials in the surrounding geological structures. Accordingly, examination of water for the presence of these contaminants is often desirable, even when the water may appear to originate from a pristine source.
Radiochemical analysis methods have been developed for determining the existence and level of such contamination. Current methods generally include multiple steps including an initial concentration step, in which the contaminants are removed from the sample, for example with an extraction medium, e.g., a chromatographic column or a filtration material, followed by purification of the contaminant and subsequent quantification of the radionuclide of interest. One example of such multi-step procedures is described in U.S. Pat. No. 6,126,901 to Patch, et al.
Researchers have also proposed methods for the direct determination of the presence of the radiochemicals while still on the extraction medium. For example concentration and direct detection of gamma-ray radiation on a column has been described (see, e.g., Link, J. M., Analytical Chemistry, 71 (1999) 2700-2707, and Headrick, J., Analytical Chemistry, 72 (2000) 1994-2000) as has concentration and direct detection of beta-particle radiation (see, e.g., Bosworth, N., Nature, 341 (1989) 167-168; Li, M., Analytical Chemistry, 66 (1994) 824-829, and U.S. Pat. No. 4,568,649 to Bertoglio-Matte). U.S. Pat. No. 6,303,936 to DeVol, et al. discloses an extraction-scintillation medium of substantially free-flowing, porous, solid particulate matter having one or more fluors retained within the particulate matter and an extraction agent adsorbed or otherwise bound to the surface of the particulate matter for the concentration and direct detection of, e.g., alpha-particle radiation. The devices of DeVol, et al. can be beneficially located in-line for monitoring the effluent from an industrial or research facility. U.S. Pat. No. 6,139,749 to Goken, et al. discloses a sorptive or reactive separator that can be incorporated in particulate form via embedding in a porous web or membrane or via attachment of the separator moiety to fibers of a fibrous matrix.
While the above described methods and materials describe certain advances in the art, room for improvement and further advances exist.